[lld] r306527 - [ELF] - Do not crash when LLD synthesizes output sections with BYTE commands and -r

[George Rimar via llvm-commits]

Author: grimar
Date: Wed Jun 28 02:59:34 2017
New Revision: 306527

URL: http://llvm.org/viewvc/llvm-project?rev=306527&view=rev
Log:
[ELF] - Do not crash when LLD synthesizes output sections with BYTE commands and -r

This is PR33596. Previously LLD would crash
because BYTE command synthesized output section,
but it was not assigned to Sec member of OutputSectionCommand.

Behaviour of -script and -r combination is not well defined,
but it seems after this change LLD naturally inherits behavior of
GNU linkers - creates output section requested in script and does not
crash anymore.

Differential revision: https://reviews.llvm.org/D34676

Added:
    lld/trunk/test/ELF/relocatable-script.s
Modified:
    lld/trunk/ELF/Writer.cpp

Modified: lld/trunk/ELF/Writer.cpp
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/Writer.cpp?rev=306527&r1=306526&r2=306527&view=diff
==============================================================================
--- lld/trunk/ELF/Writer.cpp (original)
+++ lld/trunk/ELF/Writer.cpp Wed Jun 28 02:59:34 2017
@@ -1014,13 +1014,13 @@ findOrphanPos(std::vector<BaseCommand *>
 }
 
 template <class ELFT> void Writer<ELFT>::sortSections() {
+  if (Script->Opt.HasSections)
+    Script->adjustSectionsBeforeSorting();
+
   // Don't sort if using -r. It is not necessary and we want to preserve the
   // relative order for SHF_LINK_ORDER sections.
   if (Config->Relocatable)
-    return;
-
-  if (Script->Opt.HasSections)
-    Script->adjustSectionsBeforeSorting();
+      return;
 
   for (BaseCommand *Base : Script->Opt.Commands)
     if (auto *Cmd = dyn_cast<OutputSectionCommand>(Base))

Added: lld/trunk/test/ELF/relocatable-script.s
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/test/ELF/relocatable-script.s?rev=306527&view=auto
==============================================================================
--- lld/trunk/test/ELF/relocatable-script.s (added)
+++ lld/trunk/test/ELF/relocatable-script.s Wed Jun 28 02:59:34 2017
@@ -0,0 +1,7 @@
+# REQUIRES: x86
+# RUN: llvm-mc -filetype=obj -triple=x86_64-unknown-linux -o %t1.o %s
+# RUN: echo "SECTIONS { .foo : { BYTE(0x0) } }" > %t.script
+# RUN: ld.lld -r %t1.o -script %t.script -o %t2.o
+# RUN: llvm-readobj -sections %t2.o | FileCheck %s
+
+# CHECK:  Name: .foo